1. Field of the Invention
The present invention relates to a polariscopic phase microscope that can precisely observe a specimen, and more specifically, to a polariscopic phase microscope that can observe a structure and change of a physiological cell by using a phase contrast of light passing through components of the physiological cell.
2. Description of the Related Art
An optical microscope has been mainly used for the purpose of studying in medical and biological fields. A general optical microscope is configured to perform a method that directs light on a specimen, allows the light passing through the specimen to reflect a magnified real image on an objective lens, then re-magnifies the real image through an ocular lens, and observes the re-magnified real image. However, when the general optical microscope observes the biological specimen such as the physiological cell, there is a problem in that it cannot completely perform the observation due to characteristic of the physiological cell, because it is transparent in a visible ray region. As a result, light is not absorbed other than a circumferential portion of the physiological cell. Therefore, microscopes have been developed to completely observe the biological specimen.
An example of such a microscope may include a phase-contrast microscope and an Differential interference microscope (DIC microscope). First, the phase-contrast microscope, which is a microscope devised to be able to observe the biological specimen by using a difference in a refractive index unlike the general optical microscope, observes the biological specimen using a method of a phase contrast generated due to an interference phenomenon between a diffracted beam and a non-diffracted beam as a difference in light and shade.
Meanwhile, the Differential interference microscope is a microscope that can observe the biological specimen using the inference phenomenon of an optical wavelength with a method that overlaps an object light transmitting the specimen with the interference light separated from a light source by using a characteristic that allows an object to delay a light transmitting rate when light passes through the object.
The method that observes the specimen using the phase contrast is an very useful method for a thin specimen. For example, a cultured cell in a test dish is transparent in a visible wavelength and thus, can not be observed by the naked eye. However, there is a slight difference in a refractive index between the cell and an suspension solution around the cell as well as a slight difference between a cytoplasm and a cell sap. The method using the phase contrast can observe the slight refractive index difference as described above by using the optical apparatus. The method transforms the optical path length difference of sample into different light intensities. While the light passes through the cytoplasm, the cell sap, and water, the light path is changed due to the difference in the refractive index.
At this time, if the refractive index increases for one material, the speed of light becomes slow. Therefore, the light wave passing through the cell sap is delayed more than the light wave passing through suspension media such that the following phenomenon occurs. This phenomenon is referred to as a phase change. That is, the light wave is still in an in-phase before the light completely enters the inside of the specimen, but after the light passes through the specimen, the phase of the light wave is changed. Therefore, the phase change depends on the type of materials in the path through which the light passes and the difference of the optical path occurring at the time of transmitting.
The phase-contrast microscope and the differential interference microscope can observe the biological specimen such as the physiological cell, which cannot be observed by the existing optical microscope, by transforming the different phase information into different intensities of light due to the difference in the refractive index. However, since the method using the phase contrast and differential phase contrast provides only qualitative phase information of the cell, there is a problem in that it has a limitation in accurately analyzing the biological specimen quantitatively. Therefore, apparatuses, which can provide quantitative information regarding the biological specimen, have been developed.
To this end, a method capable of imaging the quantitative phase information regarding the biological specimen has been researched. First, an apparatus that measures the phase, phase dispersion, and birefringence of the physiological cell by using an optical coherent tomography (OCT) to extract the quantitative phase information regarding the physiological cell, thereby imaging the inside of the physiological cell, and an apparatus that studies electrical characteristics of the stopped physiological cell and the inside of the physiological cell by using a phase sensitive OCT, and the like have been developed. However, since the apparatuses use a single point measuring method, they have a limitation in view of a measurement speed and there are problems in that they require a high-speed scan apparatus in order to implement the completed image, which causes mechanical noise.